Transportable or portable risers using telescoping braces are known. One such portable riser is disclosed in U.S. Pat. No. 5,381,873 for a Portable Riser Unit with a Telescoping Brace issued on Jan. 17, 1995 to Kniefel et al, and incorporated herein by reference. Portable risers typically comprise a series of stepped decks supported above the floor by a frame structure. Portable risers comprise separate or individual decks, platforms or riser cells of varying height that are connected to form a single stepped portable riser unit. The terms portable riser, transportable riser, riser, riser unit, portable riser unit or support platform are commonly used to described portable risers and are understood by those of ordinary skill in the art to be used interchangeably.
Typical risers are designed and built with the intent of being easy to transport in a folded or collapsed configuration and for rapid set-up to an upright locked use position. However, existing riser designs, such as that disclosed in U.S. Pat. No. 5,381,873, have a variety of drawbacks that remain unaddressed. For example, when setting up a transportable riser from an unfolded and collapsed position, existing portable risers typically require a considerable amount of force applied by an operator to “lift” the collapsed riser decks to an upright use position. The operator must bend his body over the riser unit, and activate a riser set-up mechanism while simultaneously applying a lifting force to lift the collapsed riser decks until the whole riser unit is upright and locked in a use position. The set-up process requires the exertion of force that is or can be awkward and physically uncomfortable for the operator especially since the operator must exert and apply a large set-up lifting force from a bent-over position. This portable riser set-up process exposes operators to possible back strain or injury. Further, the set-up process generally takes an extended time period to complete when carried out by one operator as the operator may proceed cautiously to avoid injury from application of the required set-up force.
In some instances, multiple operators may participate in the set-up process to speed up the set-up process of the portable riser units and to reduce operator injuries. Two or more operators provide the required set-up lifting force instead of one. This scenario can lead to faster set-up times and reduces operator injury rates but may be unduly expensive due to the labor cost of the additional operators.
Additionally, existing portable riser designs oftentimes unexpectedly and suddenly collapse during the set-up process when the portable riser is upright but not yet in a locked position. If the unlocked riser begins to collapse, the riser unit will completely and rapidly collapse unless the operator actively intervenes to slow the riser units' collapse by bending over the riser unit and applying a countervailing force to slowly lower the riser decks to the floor. Further, the sudden collapse of existing riser units can lead to floor damage where the riser unit is being set-up and added wear and tear on the riser unit itself.
Moreover, existing portable risers typically use operator actuated locking mechanisms to lock the potable riser in a locked upright use position. Existing locking mechanisms include hand-operated wedging locks and foot-operated latching mechanisms. These locking mechanisms typically use a telescoping tube that acts as a diagonal brace across the tubular space frame of the portable riser. The foot-operated latching mechanism can also use a spring-loaded pin and safety enclosure to additionally allow for convenient unlocking of the portable riser from the erect or use position. These operator actuated locking mechanisms highlight another drawback of existing portable risers. In existing portable riser designs, the locking mechanism is the only mechanism maintaining the portable riser in an upright and locked use position. A failure of the locking mechanism will lead to the sudden and unexpected collapse of the entire portable riser endangering and possibly injuring people standing on or in the vicinity of the portable riser.
There is thus a need for a transportable or portable riser having an improved lifting and locking assembly that will enable rapid and easy set-up of the portable riser from a folded and collapsed position to an upright locked use position with minimal operator actuation force and that can maintain the portable riser in the upright and locked use position in the event of failure of the locking mechanism.